Transmissible gastroenteritis virus (TGEV) is a highly contagious, enteric disease of swine characterized by vomiting, severe diarrhea, and a high mortality in piglets under two weeks old. Although swine of all ages are susceptible to TGEV, the mortality rate in swine over five weeks old is very low.
The first reported occurrence of TGEV in the United States was in 1945. Subsequent to its recognition in the United States, TGEV has been reported in Japan, England, many European countries, Taiwan. Central and South America and Canada.
In the densely swine-populated areas of the midwestern United States, TGEV is recognized as one of the major causes of sickness and death in piglets. "Swine producers are especially apprehensive about this disease because (1) mortality is high in newborn pigs; (2) there is no effective, practical treatment; (3) entrance of the virus into a herd in winter months is difficult to prevent because of the probable role of birds, especially starlings; and (4) the commercial vaccine available (1979) is of limited effectiveness." (E H. Bohl, "Transmissible Gastroenteritis", in Diseases of Swine. A.D. Leman et al, eds., 5th edition (1981)).
For a detailed review of TGEV see Bohl, supra.
Porcine TGEV is a coronavirus. One major problem with coronavirus infections is the unavailability of a rapid and efficient means for identifying and quantifying viruses in infected animals. Such a test is important not only for differentiating coronaviruses from other agents that cause similar disease, but also for determining the mechanism by which coronaviruses perpetuate enzootic or epizootic outbreaks. A sensitive test is also needed to determine the role of coronaviruses in acute enteric diseases of man, putative zoonoses, and chronic diseases of animals and man for which causes are not yet known. Further, an effective TGEV vaccine comprising a TGEV polypeptide would also be useful. Some of the polypeptides of the instant invention function as such vaccines.